JPH0664079B2 - A hitless speed detector in a wheel speed detection system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a hitless rotation speed detection device in a wheel speed detection system, and more specifically, to a maximum speed that can be detected by this system in a wheel speed detection system. The present invention relates to a hitless rotation speed detection device in a wheel speed detection system that enables accurate rotation speed even when the range is switched to a region higher than the determined maximum hourly speed.

[Conventional technology]

A means using a pulsar is known as a means for measuring the vehicle body speed and wheel speed of a vehicle such as an automobile.

This pulsar has teeth formed in a gear shape along the outer periphery of a pulsar body made of, for example, a disc-shaped metal, and the pulsar is mounted on the immediate side of a wheel (tire) coaxially with the axle. A sensor including a permanent magnet and a coil is arranged near the teeth formed on the outer periphery of the pulsar, and a magnetic circuit and a coil formed by the teeth of the pulsar, the permanent magnet and the coil are provided. The voltage generated during the period is detected, and the detected voltage is shaped into a predetermined waveform to measure the number of revolutions of the pulsar, that is, the tire in a predetermined time. Then, the wheel speed or the vehicle body speed is detected by an appropriate arithmetic circuit based on the measurement result.

An example of a wheel speed detection system using such a pulsar will be described with reference to FIG. The rotation speed of the wheel is detected from the pulsar 101 and sent to the frequency dividing circuit 102 as digital data. The output terminal of the frequency dividing circuit 102 is connected to the input terminal of the counter 103, and the counter 1
The output terminal of 03 is connected to the division circuit 104, and the division circuit 104 performs an operation for converting the rotation speed into an hour speed. The output terminal of the division circuit 104 is sent to the CPU 105 composed of a microcomputer or the like.

A signal is sent from the output terminal A of the CPU 105 and input to the second input terminal of the frequency dividing circuit 102.

[Problems to be solved]

By the way, in the wheel speed detection system shown in FIG. 4, the maximum speed that can be measured using this system is set to 125 km / h, for example. When the speed is 125 km / h or less, the data obtained from the pulsar 101 is the frequency dividing circuit 1
Go straight through 02 and go straight to counter 103
Then, it is sent to the division circuit 104. When the vehicle travels through such a route, the wheel speed is naturally detected correctly.

However, if the speed of the vehicle is, for example, 150 km / h, as in the case of 125 km / h or less as described above, if the signal is directly input to the counter 103 through the frequency dividing circuit 102, the counter 103 will be 125 km / h.
Numbers above / h will overflow and accurate counting will not be possible.

Therefore, in such a case, in the CPU 105, 12
It is judged that the speed exceeds 5 km / h, and in that case C
A signal is sent from the A output terminal of the PU 105 to the second input terminal of the frequency dividing circuit 102, the data input from the pulser 101 is frequency-divided by the frequency dividing circuit 102, and then sent to the counter 103.

According to such means, for example, the above-mentioned 150 km /
Even in the case of h, the counter 103 is supplied with a value that does not overflow by passing through the frequency dividing circuit 102. That is, for example, if the frequency dividing circuit 102 divides the frequency by 1/2, 150 km /
The number of pulses corresponding to h is naturally the number of pulses corresponding to 75 km / h. By doing so, the counter 103 apparently works accurately and the output data is sent from the counter 103 to the division circuit 104.

However, such means have the following problems. That is, to explain this problem with reference to FIG. 3, it is assumed that the frequency division instruction is output from the CPU 105 at the timing P. However, it is still 1 /
It is not a result of being divided by 2, and the value before the division is output as it is. Therefore, the data before frequency division is supplied to the counter 103, and if the division circuit 104 performs division based on the data before frequency division and the division result is doubled as it is in the CPU 105, malfunction may occur. Become. That is, in the CPU 105, the instruction for frequency division is issued from the A output terminal by the frequency dividing circuit 1.
However, the data before frequency division is input to the input terminal of the CPU 105. In this way, the instruction after frequency division and the data before frequency division exist in the CPU 105 at the same time, and the vehicle speed detection system as a whole malfunctions.

[Means for solving problems]

In order to solve the above problems, the present invention provides a wheel speed detecting system for detecting the number of rotations of a wheel of a vehicle, wherein a rotation information detecting means for extracting the rotation information of the wheel from information from a pulsar arranged near the wheel. And a frequency dividing circuit to which the output of the rotation information detecting means is supplied,
A counter to which the output of the frequency dividing circuit is supplied, a division circuit to which the output of the counter is supplied, and if the rotation information is below a predetermined value, the information from the rotation information detecting means is not divided. Is directly introduced into the counter for counting, and if the rotation information has a value exceeding a predetermined value, it is divided until the first pulse immediately after being divided by the dividing circuit is completed. Previous information is adopted, and when the first pulse is completed, the CPU is provided with a CPU that controls the frequency dividing circuit so as to determine the wheel speed by performing calculation based on the pulse after frequency division. .

[Action]

According to the present invention, even after the CPU issues a frequency division instruction, the data before frequency division is supplied to the CPU only after confirming that the frequency division pulse is actually frequency-divided. Become.

Further, the data after the frequency division is supplied at this point only after it is confirmed that the frequency division is performed as described above.

Therefore, in the CPU, either the data before the frequency division or the data after the frequency division is surely supplied in a properly organized form, so that the CPU may make an incorrect decision. Therefore, the wheel speed detection system can operate accurately.

〔Example〕

Hereinafter, a hitless rotation speed detection device in the wheel speed detection system of the present invention will be described based on the illustrated embodiment.

FIG. 1 is a flow chart showing the overall operation of a hitless rotation speed detecting device showing an embodiment of the present invention.

FIG. 2 is a block diagram of a hitless number-of-revolutions detecting device showing an embodiment of the present invention. In this block diagram, the members already described in FIG. Avoid repeating explanations.

Further, FIG. 3 is a time chart of the rotation speed detecting device shown in FIG.

As shown in FIGS. 1, 2, and 3, the wheel rotation speed is
Detected by 01. In this state, if the rotation speed of the wheels is equal to or lower than a predetermined value (for example, equal to or lower than the rotation speed corresponding to 125 km / h), in this case, the frequency divider circuit 102 is not operated and the data output from the pulsar 101 is counted. It enters 103 and is sent to the division circuit 104 and the CPU 105 through appropriate processing. In this case, of course, the hitless phenomenon does not occur and the normal vehicle speed is detected.

Further, the value detected by the pulsar 101 exceeds a predetermined value (for example, a value exceeding the rotational speed corresponding to 125 km / h).
, The divided pulses BP ₁ , B in FIG.
Between P ₂ and BP ₃ , the data before frequency division remains C
It is taken in as data of the PU 105. That is, the third
In the figure, when the first frequency division pulse "BP ₃ " comes, as shown in "CPU data acquisition timing" ,,, are processed as they are before the frequency division, and "CPU data acquisition timing""But,
,,, ... When it becomes, it is processed as data after frequency division.

In other words, the first divided pulse (B
The processing is performed as the data before the frequency division until P ₃ ) ends, and the processing after the frequency division is performed for the first time at the time when the first dividing pulse (BP ₃ ) ends.

Therefore, accurate data is always supplied to the CPU 105 even if the range is switched at the highest speed.

〔effect〕

According to the present invention, the CPU can determine whether the data is before the frequency division instruction or after the frequency division instruction.
PU does not cause confusion.

Therefore, it is possible to detect the hitless rotation speed without confusion even when switching the range at the highest speed.

[Brief description of drawings]

FIG. 1 is a flow chart showing the entire operation of the hitless circuit number detection device in the wheel speed detection system of the present invention, and FIG. 2 is the rotation speed used to realize the flow chart shown in FIG. FIG. 3 is a block diagram of the detection device, FIG. 3 is a time chart of the rotation speed detection device shown in FIG. 2, and FIG. 4 is a block diagram showing a conventional rotation speed detection device. 101 ... Pulsar, 102 ... Division circuit, 103 ... Counter, 104 ... Division circuit, 105 ... CPU.

Claims (1)

[Claims] 1. A wheel speed detecting system for detecting the number of rotations of a vehicle wheel, comprising: a rotation information detecting means for extracting wheel rotation information based on information from a pulsar arranged near the wheel; and this rotation information detecting means. A frequency divider circuit to which the output of the frequency divider circuit is supplied, a counter to which the output of the frequency divider circuit is supplied, a division circuit to which the output of the counter is supplied, The information from the information detecting means is directly introduced into the counter without being divided and counted, and if the rotation information is a value exceeding a predetermined value, the first shot immediately after being divided by the dividing circuit. The frequency dividing circuit adopts the information before frequency division until the end of the pulse, and when the first pulse ends, performs the calculation based on the pulse after the frequency division to determine the wheel speed. And a CPU for controlling Rotation speed detecting apparatus which hitless in wheel speed output system, characterized in that the.